Download The Effect of Aqueous Extract of the Leaves of Eucalyptus Globules

1735-2657/07/62-239-240
IRANIAN JOURNAL OF PHARMACOLOGY & THERAPEUTICS
Copyright © 2006 by Razi Institute for Drug Research (RIDR)
IJPT 6:239-240, 2007
SHORT COMMUNICATION
The Effect of Aqueous Extract of the Leaves of
Eucalyptus Globules on the Blood Glucose Level in
Fasted Rats
SHAHBAA MUSLEM ISMAIL
For author affiliations, see end of text.
Received June 25, 2007; Revised December 8, 2007; Accepted January 21, 2008
This paper is available online at http://ijpt.iums.ac.ir
ABSTRACT
The aim of this study is to determine the effect of the aqueous extract of the leaves of Eucalyptus globules on blood glucose level in fasted rats, and to find a new medical adjunct to anti-diabetes drugs. The
aqueous extract of Eucalyptus was administered in various doses (150-400 mg/kg) orally. Blood glucose
level was checked 2-6 h after treatment. The study showed that oral administration of the extract (250
mg/ kg) resulted in significant decrease in blood glucose level peaking at 4 hours, in a dose-dependent
manner (p< 0.0005). This effect declined after 6 hours of feeding in all the doses examined (150 , 250 ,
400 mg/kg body weight).These data indicates that Eucalypyus globules represents an effective antihyperglycemic adjunct for the treatment of diabetes and a potential source for the discovery of new orallyactive agent in future .
Keywords: Eucalyptus globules, Antihyperglycemic plant,Ddiabetes mellitus
Plants have been considered as a source of medicinal
agents for the treatment of various diseases. Although
present therapy for diabetes mellitus relies on an arsenal
of drugs developed since the introduction of insulin [1],
many traditional plants treatments for diabetes mellitus
have been described [2-45], few received scientific or
medical scrutiny. Eucalyptus globules (eucalyptus, blue
gum tree) are traditionally used to treat diabetes in
South America, Africa, and Asia [6], the medicinal part
of the plant are the leaves from which tea is made [7].
The use of Eucalyptus globules leaves in the treatment of diabetes mellitus was first advocated by Faulds
[8]. Recent studies in streptozotocin diabetic mice confirm the anti-hyperglycemic efficacy of eucalyptus
[9,10]. Also, Vallasensor & Lamadrid showed that
Eucalyptus tereticonis exhibit anti-hyperglycemic activity upon using oral glucose tolerance test [11,12].
Leaves of eucalyptus are reported to contain eucalplol
(cineol) together with rutin, terpineol, sesquiterpene,
alcohols, aliphatic aldehydes , isoamyl alcohol ,ethanol
terpenes and tannins [11]. The present study was undertaken to confirm the anti-hyperglycemic properties of
three doses of the aqueous extract of the leaves of eucalyptus in normal fasted rats.
MATERIAL AND METHOD
Dried eucalyptus leaves were obtained from commercial source and a voucher specimen of the plant was
identified at the National Herbarium of Iraq Botany Directorate in Abu-Ghraib. The leaves were shed dried at
25 C and homogenized to a fine powder and stored at
room temperature 20°C until use. Aqueous extract of
eucalyptus were prepared by decoction process of powdered material [10]. In brie, a suspension of 25 g of the
Eucalyptus leaves powder in 100 ml of distilled water
was stirred overnight (16 hours) at room temperature ,
and this was repeated for three consecutive times. The
residue was removed by filteration and the extract was
evaporated to dryness at a low temperature (40°C) under
reduced pressure in a rotatory evaporator. The residual
extract which was 25 % concentration were dissolved in
normal saline whenever used in the experiments [2].
Male adult Wister rats (250-300 g weight) from a
colony bred at college of Pharmacy animal house were
used in this study. Animals were housed in an airconditioned animal room and fed on pellets and water.
Animals were deprived of food but allowed free access
to tap water prior to the experiment. Collection of blood
samples from rats was maintained by cardiac puncture
IJPT | July 2007 | vol. 6 | no. 2 | 239-240
240 | IJPT | July 2007 | vol. 6 | no. 2
Fig 1. The effects of Different Doses of Eucalyptus on Blood
Glucose Concentration
technique. The rats were slightly anaesthetized with
sodium pentobarbitone administered intraperitoneally at
a dose of 30 mg/kg body weight, 30 minutes prior to the
experiments [2]. The whole blood glucose level was
estimated using the arsenomolybdate methos [12]. Sodium floride (2 mg) and 6 mg potassium oxalate /1 ml
blood were added to the blood tubes to inhibit glycolytic
enzymes and to prevent blood coagulation.
Four groups of fasted rats, six in each were used.
Three groups were fed with 150, 250 or 400 mg/kg
body weight of the aqueous crude extract of the Eucalyptus leaves dissolved in 2 ml normal saline. The forth
group was fed with 2 ml normal saline and served as
control group. Blood samples were collected at zero, 1,
2, 4 and 6 h after feeding the fasted rats with the three
examined doses of eucalyptus aquous extract of leaves
and the control . All the results were analyzed statistically using Student-t test for paired data of different
levels of significance. All the results were represented
as mean±standard error.
RESULTS
The mean of blood glucose level in normal fasted
rats was 87.7 mg /100 ml ranging from 80-96
mg/100ml. Upon oral administration of 150 mg/kg of
eucalyptus extract, there was no significant differences
in the in blood glucose level between treated and control
groups after 1 h , while it showed significant change
after 2, 4, 6 hours (p < 0.01, p < 0.01, p < 0.05 respectively), as shown in Figure 1. Notably, 250 mg/ kg body
weight of Eucalyptus leaves extract significantly lowered the fasting blood glucose levels at different time
points (p <0.01, p<0.0005, p<0.00005, p<0.05 respectively) , whereas the effect of high doses (400 mg/kg) of
the extract showed less potency in its blood glucose
lowering effect, comparing to other concentration.
CONCLUSION
Eucalyptus was reported in early studies to be an
anti-hyerglycemic agent in alloxan diabetic rabbits, with
no effect on the blood glucose concentration in normal
Ismail
rats [13]. In the present study, the anti-hyperglycemic
action of eucalyptus has been confirmed in fasted normal rats at various doses of the aqueous extract of the
leaves. This study involves a comprehensive procedure
to elucidate this point. The result proves that the eucalyptus extract causes a significant decrease in blood
glucose level in fasted rats at three different doses. As
shown in Figure 1, the onset of action of eucalyptus
extract starts 1 hour after oral feeding, peaked within 4
hours, and declines 4 hours after treatment. Our results
indicates that oral administration of aqueous extract of
Eucalyptus globules leaves at the doses of 150 and 250
mg/kg body weight exhibits a significant, dosedependent hypoglycemic effect in fasted rats , which
represents an effective anti-hyperglycemic dietary adjuncts for treatment of diabetes mellitus and a potential
source for discovery of new orally-active component for
future dietary therapy. Further studies needed to find the
active ingredient of the extract and its mechanism of
action as well as the its possible toxicities.
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CURRENT AUTHOR ADDRESSES
Shahbaa Muslem Ismail, Pharmacy Department, Medical Technical
Institute - Mansour,Technical Education Foundation, Baghdad,
Iraq. E-mail: [email protected]